This application is based upon, claims the benefit of priority of, and incorporates by reference, the contents of Japanese Patent Application No. 2002-125858 filed Apr. 26, 2002 and No. 2002-164359 filed Jun. 5, 2002.
1. Field of the Invention
The present invention relates to a composite auxiliary machine for a vehicle and a control unit thereof that are suitably applied to a refrigeration cycle device installed in a vehicle having an idling-stop function which automatically shuts off the engine when the vehicle stops.
2. Description of the Related Art
Vehicles incorporating the xe2x80x9cidling-stopxe2x80x9d function for better fuel economy have appeared on the market in recent years. With idling-stop the engine automatically shuts off when the vehicle stops moving, without turning off the ignition. In a conventional vehicle this means that the air-conditioning stops working during the stop because the compressor of the refrigeration cycle device also stops when the power from the engine is stopped.
The present inventors have shown a composite auxiliary machine for a vehicle in Japanese Patent Application No. 2001-111054 that can resolve this problem. This composite auxiliary machine for a vehicle combines an electric motor/generator with a compressor, and incorporates a torque distributing mechanism which is connected to the engine, motor/generator, and compressor respectively via engaging shafts. A locking mechanism is provided to the engaging shaft of the compressor, and a clutch is provided between the engaging shafts of the electric motor/generator and compressor.
This system not only allows the powering of the compressor by the electric motor/generator during stoppage of the engine but also enables flexible operation of the electric motor/generator and compressor in accordance with the operational state of the engine. The system also achieves simplification of its construction by integrating the electric motor/generator and its drive circuit.
Nevertheless, there is still a need for further improvement in the above invention with respect to the complexity in controlling both the locking mechanism and the clutch when regulating the operational performance of the compressor.
In view of the foregoing, an object of the present invention is to provide a composite auxiliary machine for a vehicle and a control unit thereof by which performance control of the compressor is readily achieved. To achieve the above object, the present invention employs the following technical means.
According to a first aspect of the present invention, a composite auxiliary machine for a vehicle includes a compressor (140) for compressing a refrigerant in a refrigeration cycle device (200), a rotary machine (130) functioning as a generator and as an electric motor, and a torque distributing mechanism (150) for distributing torque of a drive shaft (112). The drive shaft (112) is rotated by a driving force of a vehicle engine (10).
The torque distributing mechanism (150) distributes torque to a compressor shaft (142) of the compressor (140) and to a shaft (132) of the rotary machine (130), and distributes torque input from the shaft (132) of the rotary machine (130) to the drive shaft (112) and to the compressor shaft (142). Additionally, an intermittent means (120) provided to the torque distributing mechanism (150) connects and disconnects any two of the drive shaft (112), the compressor shaft (142), and the shaft (132) of the rotary machine (130). A locking mechanism (160) restricts rotation of the compressor shaft (142). The compressor (140) includes a variable displacement mechanism (145, 148) for varying an amount of discharge per turn of the compressor shaft.
In this composite auxiliary machine (100) for a vehicle, the intermittent means (120) is connected while the vehicle engine (10) is running, so that torque is transmitted from the drive shaft (112) to the compressor shaft (142) and the shaft (132) of the rotary machine (130) via the torque distributing mechanism (150) and the compressor (140) and the rotary machine (130) are activated simultaneously, whereby operation of the refrigeration cycle device (200) by the compressor (140) and power generation by the rotary machine (130) are both achieved.
While the compressor (140) is operating, the intermittent means (120) remains connected, and an amount of discharge of the compressor (140) is readily changeable in accordance with a predetermined thermal load of the refrigeration cycle device (200) by means of the variable displacement mechanism (145, 148). Because changing the amount of discharge does not involve switching the intermittent means (120), favorable drivability is achieved.
When the vehicle engine (10) is stopped, the intermittent means (120) is disconnected, and the rotary machine (130) is operated as an electric motor and provides power to the compressor (140) through the torque distributing mechanism (150). This permits the compressor (140) to continue providing air-conditioning. In this state also, in which the intermittent means (120) is disconnected, an amount of discharge of the compressor (140) is readily changeable by means of the variable displacement mechanism (145).
Operating the rotary machine (130) as an electric motor in this state with the intermittent means (120) being disconnected and the compressor shaft (142) being restricted by the locking mechanism (160), will rotate the drive shaft via the torque distributing mechanism (150) thereby restarting the vehicle engine (10).
According to a second aspect of the invention, a planetary gear (150) should preferably be used as the torque distributing mechanism (150). When the intermittent means (120) is connected while the engine (10) is running, because of the characteristics of the planetary gear (150), both the compressor shaft (142) and the shaft (132) of the rotary machine (130) rotate with the same rpm as that of the drive shaft. Accordingly, the rotary machine (130) can carry on stable power generation without being affected by changes in the amount of discharge of the compressor (140).
According to a third aspect of the invention, the locking mechanism (160) may be a one-way clutch (160) that allows forward rotation of the compressor shaft (142) and inhibits reverse rotation of the same. Thereby, the locking of the compressor shaft (142) at the time of starting the engine (10) is performed mechanically. Thus the locking mechanism (160) requires no control, and can be simply constructed.
According to a fourth aspect of the invention, the drive shaft (112) is connected to a planetary carrier (152) of the planetary gear (150), the compressor shaft (142) is connected to a ring gear (153) of the planetary gear (150), the shaft (132) of the rotary machine (130) is connected to a sun gear (151) of the planetary gear (150), and the intermittent means (120) is disposed between the drive shaft (112) and the compressor shaft (142). Thereby, the rotary machine (130) can be constructed compactly and when working as an electric motor, it can provide the same level of power to the compressor (140) or to the vehicle engine (10) at reduced rpm but with increased torque transmission.
According to a fifth aspect of the invention, a limiter mechanism (170) is interposed between the torque distributing mechanism (150) and the compressor shaft (142) for discontinuing the torque transmission between the drive shaft (112) and the compressor shaft (142) and between the shaft (132) of the rotary machine (130) and the compressor shaft (142) when the compressor (140) is locked. Thereby, even if the compressor (140) should be locked for some reason, the vehicle engine (10) and the rotary machine (130) are protected. Therefore, functions related to the drive are not impaired.
According to a sixth aspect of the invention, the limiter mechanism (170) should preferably be disposed closer to the compressor (140) than the one-way clutch (160). Thereby, even when the limiter mechanism (170) is working, the one-way clutch (160) can still restrict the compressor shaft (142) for starting the vehicle engine (10).
The torque distributing mechanism (150) is a significant component as it achieves torque transmission, and thus needs to have good reliability in terms of durability. Therefore, according to a seventh aspect of the invention, the torque distributing mechanism (150) should preferably be located inside an enclosed space (150b), and the drive shaft (112), the shaft (132) of the rotary machine (130), and the compressor shaft (142) should preferably be provided with sealing members (300a-300d) at portions extending into the enclosed space (150b).
Thereby, pre-applied lubrication oil in the torque distributing mechanism (150) is prevented from leaking outside of the enclosed space (150b), and with this lubrication oil retained inside the space, the reliability and durability of the torque distributing mechanism (150) is improved. This arrangement also prevents reliability degradation of the rotary machine (130) or the intermittent means (120) caused by contamination of the rotary machine (130) and intermittent means (120) with lubrication oil, particularly when the rotary machine (130) is a brush type and the intermittent means (120) performs connection and disconnection functions by friction.
According to an eighth aspect of the invention, the intermittent means (120) may be a clutch (120a, 120b) that works with lubrication oil and that is located inside the enclosed space (150b) together with the torque distributing mechanism (150). In such a case, the reliability of both the torque distributing mechanism (150) and the clutch (120a, 120b) is improved because of the retained lubrication oil.
According to a ninth aspect of the invention, the rotary machine (130) may be a brushless rotary machine (130) and be located inside the enclosed space (150b) together with the torque distributing mechanism (150). In this case, oil seals (300b) for the shaft (132) of the rotary machine (130) can be omitted.
According to a tenth aspect of the invention, the intermittent means (120) is a clutch (120a, 120b) that works with lubrication oil. The rotary machine (130) is a brushless rotary machine (130), and the intermittent means (120), the rotary machine (130), and the torque distributing mechanism (150) are supplied with the refrigerant.
With such a construction, the rotary machine (130) is cooled by the refrigerant, and will have better durability. It can also be constructed more compactly. Because the rotary machine (130) is of a brushless type, there is no risk that lubrication oil in the refrigerant will cause trouble to power supplied elements. Also, the torque distributing mechanism (150) and clutch (120a, 120b) will benefit from the lubrication oil in the refrigerant and will thereby have better durability and operability.
According to an eleventh aspect of the present invention, a control unit of a composite auxiliary machine for a vehicle has a function of automatically shutting off its vehicle engine (10) in accordance with its driving state. The control unit includes the composite auxiliary machine for a vehicle as set forth in any one of the first to tenth aspects, and control means (190) for controlling operations of the variable displacement mechanism (145, 148), the rotary machine (130), and connection and disconnection of the intermittent means (120).
The control of the composite auxiliary machine for a vehicle includes connecting the intermittent means (120) while the vehicle engine (10) is running, disconnecting the intermittent means (120) while the vehicle engine (10) is not running, and causing the rotary machine (130) to rotate in a reverse direction so as to operate as an electric motor for driving the compressor (140). Additionally, control consists of disconnecting the intermittent means (120) when starting the vehicle engine (10), causing the rotary machine (130) to rotate in a forward direction so as to operate as an electric motor for starting the vehicle engine (10), and operating the variable displacement mechanism (145, 148) while the compressor (140) is operating to change an amount of discharge of the compressor (140) in accordance with a predetermined thermal load of the refrigeration cycle device (200).
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. Reference numerals described in each of the above means correspond with means of the preferred embodiments described later.